The Florida-based tabloid said publishing sources familiar with Joe McGinniss' new book say "The Rogue: Searching for the Real Sarah Palin" will reveal Palin had the sexual encounter with Rice when he was a star at the University of Michigan and she was a sports reporter for KTUU-TV in Anchorage. They met while he was in town for a basketball tournament, the sources say McGinniss says in his book, which is to be published Tuesday.
The encounter allegedly occurred less than a year before she eloped with her husband Todd, the Enquirer said.
Rice, who went on to an all-star NBA career, confirmed the tryst happened, the Enquirer reported McGinniss writes in his book.
The tabloid also reports its publishing source said McGinniss confirms a 2008 Enquirer story that Palin, who went on to become a city mayor, governor of Alaska, Republican vice presidential nominee, national political commentator on Fox News and potential presidential candidate, also had a six-month extramarital affair with a business partner of her husband.
In another bombshell, the publishing source says, McGinniss writes Sarah and Todd Palin both have used cocaine.
The Enquirer story posted on its Web site carried no response from the Palins or McGinniss.